Pressurized storage tank

ABSTRACT

A prestressed concrete storage reservoir is provided for holding liquified gases. To increase the quantity of ambient gas stored in the reservoir and to permit a warmer than normal liquification temperature, the gas is stored under a substantial pressure. The structure is characterized by a prestressed sidewall system with the roof and floor systems tied together by a plurality of vertically prestressed columns, these combined systems being substantially independent of the sidewall whereby the combined systems may move substantially structurally free of the sidewall.

United States Patent [72] Inventors John J. Closner 2,932,964 4/1960 Dobell 52/224 D0uglast0n,N.Y.; 3,092,933 6/1963 Closner etal. 52/224 Morris Schupack; Eugene W. Marlowe, 3,151,416 10/1964 Eakin et a1 52/169 X bothofStamford, Conn. 3,226,894 1/1966 Burchardt etal. 52/223 [21] App1.No. 768,379 3,355,357 11/1967 Sage 52/224 X [22] Filed Oct. 17, 1968 3,408,784 11/1968 Crowley 52/224 3; i fi l I Primary Examiner-Alfred C. Perham 1 Sslgnee 232 a??? 4tt0rney-Ct1rtis,M0rris& Safford [54] PRESSURIZED STORAGE TANK M W i 8 Claims 8 Drawing 3 ABSTRACT: A prestressed concrete storage reservoir is pro- [52] U.S. (I1 52/224, "ided for holding quified B To increase the quantity 52/169, 52/741 ambient gas stored in the reservoir and to permit a warmer 5 Int CL T t T 1504c 3/26 than normal liquification temperature, the gas is stored under 50 Field M Search 52/224, a Substantial Pressure The structure is characterized y a 169,741 prestressed sidewall system with the roof and floor systems tied together by a plurality of vertically prestressed columns, [56] References Cited these combined systems being substantially independent of UNITED STATES PATENTS the sidewall whereby the combined systems may move sub- 1 895 747 1,1933 Beldimano 52/169 stantially structurally free of the sidewall. 2,558,580 6/1951 l om lgala u 52 2 24X t 1 r as a a t v \D a figs 9 u S lo v 1 v 3%? "J40 v I 80 .98 u

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PATENTEU Jul I 872 SHEET 1 [IF 3 D U D QLMZ'MYW 'ATTORNEYS msmm JAN? 1 i972 ales-3.32s SHEET 2 OF 3 ATTORN PRESSURIZED STORAGE TANK BACKGROUND OF THE INVENTION The present invention relates to the storage of liquified gases under high pressure and more particularly to structures for containing the liquified gases as well as the method of constructing such structures.

Many gases, such as natural gas, oxygen, nitrogen and the like, are economically stored at temperatures far below the usual ambient temperatures so that they may be kept in liquified condition. When these gases are liquified they are in a cryogenic state and are known commonly as cryogenic liquids. Heretofore cryogenic liquids have been stored at about atmospheric pressure but at extremely low temperatures, such as about -260 F. for liquified natural gas. The proper atmospheric pressure storage temperature for different liquified gases varies, but they are well known to those skilled in the art.

In recent years there has been considerable activity to devise means and structures for storing liquified gases. Much of the activity has been concerned with the storage of natural gas. In many places there is a seasonal demand for natural gas for use as a heating fuel and, during the period of great demand, the supply and distribution system from the supply wells is obviously under a very heavy demand load. Also, during the nonheavy demand season the supply and distribution system is normally only partially used. In order to reduce the size of the gas transmission system it has been found feasible to stockpile liquified gases for use during the peak demand time, thus making greater use ofthe supply system.

Accordingly, there have been recent improvements in storage facilities for such gases. Storage structures which are useful for this purpose are shown and described in U.S. Pat. No. 3,092,933, issued June 11, 1963 and in US. Pat. No. 2,777,295, issued Jan. 15,1957.

As shown in US. Pat. No. 3,092,933 prestressed concrete structures may advantageously be used for the storage of cryogenic liquids.

lf liquified gas stored at a cryogenic temperature is also processed and stored under substantial pressure, the temperature at which liquification occurs is higher, thus reducing the amount of liquification required. To construct such a reservoir for storing liquified gas at such temperatures and pressure presents many problems. If the concept of using a conventional reinforced concrete reservoir having a thick floor, thick roof and thick walls were used, substantial bending and temperature moment problems would be encountered where the wall connects to the roof and to the floor. The sheer weight and massiveness of the elements needed and the floor contraction difficulties would be enough to make such a construction unfeasible from the viewpoint of economics.

Accordingly, it is an object of the present invention to provide a storage system including a prestressed reservoir with suitable means for resisting the pressure within the reservoir, as well as a method of constructing the same economically.

DETAILED DESCRIPTION In the specification and the accompanying drawings, an embodiment of the present invention for the storage of pressurized liquifred gases is shown. This embodiment is not to be construed as limiting the invention but rather it is for the purpose for informing those skilled in the art so that they may practice the invention in many embodiments and within the spirit and scope of the claims which are set forth hereinafter.

IN THE DRAWINGS FIG. 1 is a partially fragmentary sectional side view of a cryogenic storage reservoir in accordance with the present invention;

FIG. 2 is a partially fragmentary quarter sectional plan view of the reservoir ofFIG. 1 taken along lines 22;

FIG. 3 is an enlarged sectional plan view of a portion of the sidewall of the reservoir of FIG. 1;

FIG. 4 is an enlarged partly fragmentary sideview of a prestressed column taken along lines 4-4 of FIG. 1;

FIG. 5 is an enlarged sectional side view of the sidewall taken along lines 5-5 of FIG. 2;

FIG. 6 is a detailed sectional side view of the sidewall and footing construction of the reservoir shown in FIG. 1;

FIG. 7 is a sectional side view of the joint between the sidewall and the floor; and

FIG. 7a is a sectional side view of an alternate joint between the sidewall and the floor.

Referring to the drawings, and to FIGS. 1 and 2 in particular, a large cryogenic storage reservoir in the form of a tank 10 is shown. The illustrated tank 10 includes a cylindrical sidewall 12 which is set on a suitable footing or foundation 14. A floor system 16 is provided and it also rests on a peripheral portion of the foundation 14. A roof system 18 is positioned within the sidewall 12.

To insure the liquid and vapor tight integrity of the tank 10, a liner 20 is provided which extends along the inner surfaces of the sidewall 12, the upper surface of the floor system 16 and the under side of the roof system 18. At point A where the liner 20 passes from the floor to the sidewall, expansion joint 22 is provided; and a similar joint 24 is provided at point B where the liner 20 passes from the sidewall to the roof.

The liner 20 is advantageously made of nickel alloy steel since it is exposed to the liquified gas at cryogenic temperatures and must be resistant to brittle fracture. Approximately 8 percent nickel is usually satisfactory.

In order to support the roof system 18 substantially independent of the sidewall 12, a series of prestressed columns 26 I are provided and act as internal ties to unify the wall and the floor systems.

A typical tank in accordance with the present invention when acting as a pressurized cryogenic storage structure advantageously may support an internal pressure of about 185 psi. and a temperature of 1 75 F. as standard operating conditions. Such a tank would have to have substantial overall dimensions and would require an interior diameter of 200 feet and an interior height of about feet to be of sufficient size to permit an economical construction. In order to resist the high internal pressure and low temperature, the sidewall 12 of such structure has an overall thickness of about 10 A feet and the supporting ring foundation 14, for a typical soil, a width of 18 feet and a height of about 6 V2 feet. The floor and the roof systems 16 and 18 each would have a thickness of approximately 5 to 6 feet.

It will be noted that the thickness of the roof and floor system is relatively thin when one considers the internal pressure and the diameters and height of the tank. This thin floor and roof construction is made possible by the use of the prestressed tie columns 26 spaced within the tank on centers of about 5 feet so that the floor and roof systems are tied together and are adapted to be moveable substantially independent of the sidewall.

METHOD OF CONSTRUCTION In order to construct the illustrated tank 10, it is necessary that the soil S," in which the foundation 14 will be set, be prepared properly and have sufficient strength to support the footing and the accompanying structure. The tank structure may be located where the soil is non-frost-susceptible. A frostsusceptible soil is one in which significant ice segregation will occur when the requisite moisture and freezing conditions exist.

After the soil has been properly prepared, the foundation 14 is set in place by well-known construction methods. The ring foundation 14 is preferably made discontinuous with joints about every 30 feet on the circumference where the tank is to have an inside diameter of about 200 feet. This discontinuous ring foundation advantageously minimizes the radial motion of the foundation during cooldown of the structure.

With the foundation 14 in place, the next step is to provide the sidewall 12. The sidewall is preferably placed on an insulation and support pad 28 which may be made of any suitable material such as polyvinyl chloride foam. To facilitate construction of the sidewall, a unique stave system is used. The inner portion of the sidewall 12 is formed by using precast, pretensioned vertical staves 30 which are lined on their inner surface with the liner 20. The vertical staves 30 are supported on the pad 28 and when erected serve as the interior form structure for the remainder of the sidewall 12.

In the illustrated embodiment the staves 30 consist of pretensioned precast concrets about 6 inches thick with the pretensioning helping to control the vertical thermal stresses in the concrete developed at cryogenic temperatures. The liner 20 which is attached to each stave is about three-sixteenths of an inch thick and made of approximately 8 percent nickel alloy steel, and serves as an inner wall face reinforcement. Anchors 31 attached to the inner surface of the liner 20 are embedded in the stave concrete and assure an integral construction.

The liner portions on the staves 30 are joined together by plates 33 which are welded to adjoining staves.

. The remainder of the sidewall 12 is comprised of the concrete core 32 in the outer surface of which are provided a series of recesses 34. In the recesses 34 prestressing tendons 36 are placed when the sidewall is prestressed after erection. When the tendons 36 have been placed in the recesses 34 by well-known prestressing means and apparatus, the recesses are closed off and the tendons protected by grouting or by other suitable means, such as the injection of grease or the plastic coating of the tendons. A final finish to the sidewall 12 may be provided by use of protective cover 38 made of suitable material such as steel, or polyurethane and the like, under which is a layer ofinsulation 30, such as urethane.

As a further precaution, a moisture barrier 41 may be provided in the outer portion of the sidewall 12. This barrier is substantially coextensive with the sidewall 12 and maybe formed of carbon steel since it is placed in compression by the prestressing tendons, and, therefore, not subject to brittle fracture.

While the sidewall 12 is being erected, and before prestressing if desired, the floor system 16 may also be placed.

The floor system 16 consists of an insulated layer construction which has an outer vapor barrier 40 formed of a mild steel plate about three-sixteenths of an inch thick that is laid directly on a 6 inch layer of an oil-sand base 42. The oil-sand base 42 is placed on non-frost-susceptible soil similar to that discussed previously in relationship to the foundation 14. As a precaution to prevent any freezing of the sub-base, heating cables 44 are advantageously provided if the foundation soil is frost-susceptible.

With the vapor barrier plate 40 in position, insulation 46 consisting of urethane foam or foam glass is next positioned. On top of the insulation 46 a layer of plywood 47 is placed. The plywood 47 serves to act as a protection for the insulation and a slab of concrete 48 about 6 inches thick is placed on the plywood and the slab serves as a working platform.

Base plates 50 are set on the working slab 48 and these base plates act to support the internal tie columns 26.

The tie columns 26 consist of a post-tensioned tendon 56 which is anchored to the baseplate 50, a gastight conduit 54 for a tendon 52, a top plate 56, tensioning means 58 and a reinforced concrete casing 60 surrounding the conduit 54. The conduit 54 is advantageously made of low-cost carbon steel except for the portions 62 which are adjacent to the liner 20. The intermediate portions 62 are made preferably from nickel alloy pipe, with approximately an 8 percent nickel content.

With the columns in place, the floor slab 64 may then be placed and the liner 20 placed thereon. If desired, the slab 64 may be placed first leaving space therein for the tie columns The liner 20 is joined to the intermediate portions 62 of the conduit 54 by means of splice plates 66 which are welded to the column portions 62 and to the liner 20.

With the columns in place, the roof system 18 is'next constructed. The illustrated roof system 18 consists of a roof slab of reinforced concrete 68 placed on the liner 20, if desired a lightweight concrete cover slab 70, a layer of insulation 72 of formed urethane or the like and a roofing coating 74.

As shown in FIGS. 7 and 7a in particular, an expansion joint 22 is provided at point A between the liner portion 20 overlying the floor and that which is integrally formed with the sidewall 12 and particularly as part of the precast staves 30. In FIG. 7, a concave expansion joint plate 76 is anchored to the floor system 16 and to the sidewall 12 by anchorages 78 and 80, respectively. During the cool down of the interior of the tank, the plate 76 is free to deflect as the wall 12 is moved inwardly and the tie columns 26 shorten, thus lowering the roof slab with respect to the wall. During pressurization and operation the tank walls 12 move outwardly and the slab upwardly, thus the plate 76 is free to deflect with these movements.

In FIG. 7a an alternative form or embodiment of the expansion joint 22 is shown. In this embodiment, the plate 82 joining the liner 20 overlying the fioor and liner 20 integrally formed is of a convex configuration. The convex plate 82 is anchored by anchorages 78 and 80 in a manner similar to that for holding the concave plate 76 in place. However, the convex arrangement of FIG. 7a has greater strength since a load placed against the plate 82 will have reaction point not only at the anchorages 78 and 80, but also against the liner 20.

While the liner 20 has been shown in the illustrated embodiment as indirect contact with the concrete wall staves, floor and roof, it may be desirable to place a layer of insulation between the liner and the concrete in some instances.

What is claimed is:

1. A structure for storing liquified gases maintained at cryogenic temperatures and high pressures comprising a floor, a sidewalls, a roof and tension members connecting the roof and floor together, said sidewall and tension members being made of prestressed reinforced concrete; the floor, roof and tension members connected together to form an integral assembly, said assembly moveable substantially independent of the sidewall.

2. A structure as defined in claim 1 and further including sealing means between the roof and sidewall and the floor and sidewall whereby the tank remains substantially liquidtight under high pressure.

3. A structure as defined in claim 1 wherein the tension members connected to the floor and roof are prestressed concrete columns comprised of prestressing tendons of highstrength steel encased in concrete, said tendons anchored to the floor and roof and tensioned so that the concrete in the columns is in a state of compression when the interior of the structure is not under high pressure.

4. A structure as defined in claim 1 and further including a liner within the structure comprised of a material resistant to brittle fracture.

5. A structure as defined in claim 1 and further including an expansion joint having a convex shape between the sidewall and the floor system.

6. A structure for storing liquified gases maintained at cryogenic temperatures and high pressures comprising a floor system, a sidewall, a roof system and tension members connecting the roof and floor system together, said sidewall including a concrete core having an inner surface with an attached liner of steel resistant to brittle fracture and an outer surface having a plurality of recesses adapted to receive tendons for prestressing said wall and an insulation system thereon, said floor system including a outer vapor and moisture barrier, an insulation layer and a concrete slab, said roof system including a concrete slab, an insulation layer and an outer coating, said tension members comprising high-tensile-strength tendons encased in concrete, said tendons connected to said floor slabs and tensioned to place the encasing concrete in compression, a liner of material resistant to brittle fracture on the inner surfaces of said floor and roof systems and connected to the liner on said sidewall by expansion joints the floor and roof systems connected by said tension members forming an integral assembly substantially independent of the sidewall.

7. A method for constructing a tank for holding liquified gases at cryogenic temperatures and high pressure, and including a foundation, a sidewall, a floor, a roof and tie columns between the floor and roof, comprising the steps of 1. preparing and placing a foundation in the peripheral area of the tank;

2. erecting a prestressed concrete sidewall on said foundation, said wall having a steel liner on the inner surface thereof and being an integral part of the sidewall;

3. placing a floor within the sidewall, said floor having a steel liner therewith and said liner adapted to be joined to the liner on the staves of the sidewall;

4. erecting a plurality of tie columns having post-tensioned tendons therein, said tendons being anchored to the floor and positioned within the boundary formed by the sidewall; and

5. placing a roof, said roof having a steel liner therewith and said liner adapted to be joined to the liner on the staves of the sidewall, said roof joined to the columns;

whereby the assembly of the floor roof and post-tensioned tie columns are adapted to act substantially independent of the sidewall.

8. A method as defined in claim 7 wherein the step of erecting a prestressed concrete sidewall includes erecting precast pretensioned vertical staves having a steel liner on the inner surface thereof said staves being an integral part of the sidewall and acting as the inner form for placing the remainder of the wall before prestressing the composite wall.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 633,328 Dated January 11, D72

n fl John J. Closner and Morris Schupack and Eugene Marlowe It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column U line 38, change "sidewalls" to --sidewall-; and 1 Column l, line 75, after "said" insert -roof and--,.

- Signed and sealed this 25th day of July 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK .Attesting Officer 'Comnissioner of Patents FORM PO-1050 (10-69) USCOMM-DC 60376-969 w us. GOVERNMENT PRINTING OFFICE: 1959 0-3EG-334 

1. A structure for storing liquified gases maintained at cryogenic temperatures and high pressures comprising a floor, a sidewalls, a roof and tension members connecting the roof and floor together, said sidewall and tension members being made of prestressed reinforced concrete; the floor, roof and tension members connected together to form an integral assembly, said assembly moveable substantially independent of the sidewall.
 2. A structure as defined in claim 1 and further including sealing means between the roof and sidewall and the floor and sidewall whereby the tank remains substantially liquidtight under high pressure.
 2. erecting a prestressed concrete sidewall on said foundation, said wall having a steel liner on the inner surface thereof and being an integral part of the sidewall;
 3. placing a floor within the sidewall, said floor having a steel liner therewith and said liner adapted to be joined to the liner on the staves of the sidewall;
 3. A structure as defined in claim 1 wherein the tension members connected to the floor and roof are prestressed concrete columns comprised of prestressing tendons of high-strength steel encased in concrete, said tendons anchored to the floor and roof and tensioned so that the concrete in the columns is in a state of compression when the interior of the structure is not under high pressure.
 4. A structure as defined in claim 1 and further including a liner within the structure comprised of a material resistant to brittle fracture.
 4. erecting a plurality of tie columns having post-tensioned tendons therein, said tendons being anchored to the floor and positioned within the boundary formed by the sidewall; and
 5. placing a roof, said roof having a steel liner therewith and said liner adapted to be joined to the liner on the staves of the sidewall, said roof joined to the columns; whereby the assembly of the floor roof and post-tensioned tie columns are adapted to act substantially independent of the sidewall.
 5. A structure as defined in claim 1 and further including an expansion joint having a convex shape between the sidewall and the floor system.
 6. A structure for storing liquified gases maintained at cryogenic temperatures and high pressures comprising a floor system, a sidewall, a roof system and tension members connecting the roof and floor system together, said sidewall including a concrete core having an inner surface with an attached liner of steel resistant to brittle fracture and an outer surface having a plurality of recesses adapted to receive tendons for prestressing said wall and an insulation system thereon, said floor system including a outer vapor and moisture barrier, an insulation layer and a concrete slab, said roof system including a concrete slab, an insulation layer and an outer coating, said tension members comprising high-tensile-strength tendons encased in concrete, said tendons connected to said floor slabs and tensioned to place the encasing concrete in compression, a liner of material resistant to brittle fracture on the inner surfaces of said floor and roof systems and connected to the liner on said sidewall by expansion joints the floor and roof systems connected by said tension members forming an integral assembly substantially independent of the sidewall.
 7. A method for constructing a tank for holding liquified gases at cryogenic temperatures and high pressure, and including a foundation, a sidewall, a floor, a roof and tie columns between the floor and roof, comprising the steps of
 8. A method as defined in claim 7 wherein the step of erecting a prestressed concrete sidewall includes erecting precast pretensioned vertical staves having a steel liner on the inner surface thereof said staves being an integral part of the sidewall and acting as the inner form for placing the remainder of the wall before prestressing the composite wall. 